question #41 The NYT article "Money and Medicine" discusses the work of Brent James at Intermountain Healthcare. James says, “Guys, it’s more important that you do it the same way than what you think is the right way.” To prove this (well, we won't prove it, we'll just give an example in the context of process flow), consider an operating room used by various doctors who all perform the same operation. Scenario 1 is a scenario in which each Doctor does it the way she thinks is right, such that the average process time is 20 minutes (note that the Doctor's capacity is thus 3/hr). However, doctors differ in the way they perform the process, so the variability is high; let's say the variability factor is 2. If patients are scheduled to use the room at a rate of 2 per hour, then the utilization is 67% (calculated as 2/hr divided by 3/hr). Reading the average y-value from the graph below, we find the average number of patients in the waiting room is about 2.7. Now consider scenario 2, where doctors all perform the process the same way, but it's a "worse process" in that the average process time is 25 minutes instead of 20 minutes (the capacity is cut to 2.4 per hour, for a utilization of 2.4/3 = 80%). But since all doctors are performing the process the same way, it happens to cut the variability factor to 0.5. Scenario 2 has an average process time that is 25% worse, but because it largely eliminates the variability, it performs better, reducing the inventory of patients in the queue. What is the approximate number of patients in the queue for scenario 2 (versus 2.7 for scenario 1)? quiz41